Device for free thread passage in the sewing machine



June 2, 1970 KOICHI TOMONO ETAL 3,515,033

DEVICE FOR FREE THREAD PASSAGE IN THE SEWING MACHINE I Filed Aug. 26,1968 4 Sheets-Sheet l Fi .1. 32 311718\59 58 30 36 39 11 57 1 6 26 fi\//Kmcm TOMONO,

z; (DQHIMASA DIIMM mu KOILHI rnxeunmn INVENTORS T wwmmwnw ATTORNEYS June2, 1970 DEVICE FOR FREE THREAD PASSAGE IN THE SEWING MACHINE Filed Aug.26, 1968 Fig.3.

4 Sheets-Sheet 2 20 KOICHI TOIMNO. 12 YosmMAsA mm mm Kmcm TAREHAMA,

33 INVENTOR5 ATTORNEYS June 1970 KOICHI TOMONO ETAL 3, 5,

DEVICE FOR FREE THREAD PASSAGE IN THE SEWING MACHINE Filed Aug. 26, 19684 Sheets-Sheet 8 Fig-6.

KOICHI ToNmNO. YOSHIMASA OMAHA am MILHI TAKEHAM INVENTOR$ BYIIJMUILYIIL(M.

ATTORNEY;

June 1970 KOICHI TOMONO ETAL 3,515,

DEVICE FOR FREE THREAD PASSAGE IN THE SEWING MACHINE Filed Aug. 26, 19684 Sheets-Sheet 4 United States Patent 3,515,083 DEVICE FOR FREE THREADPASSAGE IN THE SEWING MACHINE Koichi Tomono, Toyonaka-shi, YoshimasaOkada, Suitashi, and Koichi Takehama, Ibaraki-shi, Japan, assignors toSoryu Mishiu Seizo Kabushiki Kaisha, also known as The Soryu SewingMachine Mfg. Co., Ltd., Ibaraki-shi,

Japan Filed Aug. 26, 1968, Ser. No. 755,181 Claims priority, applicationJapan, Apr. 16, 1968, 43/ 25,691 Int. Cl. Db 57/10 US. Cl. 112-232 5Claims ABSTRACT OF THE DISCLOSURE A bobbin thread case is mounted in astationary inner shuttle which is positioned in a rotary outer shuttle.The outer shuttle is rotated by a shaft which also has a cam thereon.The inner shuttle is prevented from rotating by a drag which catches anarm of the bobbin thread case and a protrusion of the inner shuttle. Areverse lever is operated by the cam to temporarily rotate the innershuttle reverse to the direction of rotation of the outer shuttle.

This invention relates to a device for free thread passage in a sewingmachine equipped with a full circularly moving rotary shuttle, moreparticularly to a device for free passage of thread which facilitatesthe passage of the upper thread as it is drawn upward round the outsideof the inner shuttle. v

In the sewing machine equipped with a full rotatory shuttle, the outershuttle constantly makes a continuous rotation in one direction, a dragprovided on the lower surface of the sewing machine bed being engagedwith a notch of the inner shuttle from the necessity of preventing therotation of the said inner shuttle as well as the bobbin threadcase.fitted thereinside. The notch of the inner shuttle being inconstant contact with the drag, the upper thread which travels upwardround the outside of the inner shuttle is subjected to considerableresistance as it is necessary for the said thread to pass through thecontacting parts of the notch of the inner shuttle and the drag byforcing the said parts open.

The foregoing device is defective in that irregular tightening is apt tooccur to the upper thread, and a noise is produced by the collisionbetween the drag and the notch which are forced open by the upper threadand then restored after the passage of the said thread.

The first object of the invention is to obtain regular stitches by meansof uniform thread tightening by removing the foregoing resistancearising at the time of the passage of the upper thread, as well as tosilence the noise which arises at the time of passage of the thread.

The second object of the invention is to facilitate the adjustment ofthe timing of the shuttle rotation and that of the reverse lever whichmakes the passage of the thread easier.

The third object of the invention is to enable to use for this purposethe bobbin and bobbin thread case for the conventional home sewingmachine equipped with a semicircularly moving rotatory shuttle withoutany adapter whatsoever.

The fourth object of the invention is to stabilize the sustaining stateof the lower thread whereby to render the thread arranging board of theouter shuttle useless.

The fifth object of the invention is to facilitate the passage of thethread even when the device for free thread passage fails to functionsatisfactorily.

The sixth object of the invention is to so arrange that the thread orthe like is hardly wedged between the inner Patented June 2, 1970 andouter shuttles as well as to make it easy to remove the thread or thelike even when wedged.

The seventh object of the invention is to minimize the risk of breakageeven when the thread or the like should be wedged between the outer andinner shuttles and consequently the inner shuttle should be forced torotate together with the outer shuttle.

The eighth 'object of the invention is to simplify the manufacturingprocess as well as to reduce the weight by economizing the use of thematerials.

The foregoing several objects can be attained by the combination andfunction of the improved parts constituting this invention, and theembodiments thereof will be clarified by the accompanying drawing aswell as the detailed description hereinafter set forth.

Modifications or alterations of shapes with regard to the details of thestructures of the preferred embodiments hereinunder set forth are to beincluded in the claims which will hereinafter appear.

The invention consists of a reverse lever which, fitted into adepression formed in one part of the inner shuttle, provides a space forthe free passage of the thread at the part of the drag by causing theinner shuttle to reverse as the upper thread is passing upward from theinner shuttle, and a cam which is fixed to the shuttle shaft to make theforegoing reverse lever function, the said space being provided at thepart of the drag of the inner shuttle by'causing the inner shutttle toslightly reverse in a direction opposite to the rotation of the outershuttle, taking advantage of the reverse lever activated by the saidcam.

FIG. 1 is an elevation of the device for free thread passage of theinvention, illustrating the state wherein the reverse lever, fitted intothe depression of the inner shuttle, has caused the inner shuttle toreverse slightly.

FIG. .2 is an elevation illustrating the state wherein the reverse leverhas departed from the depression of the inner shuttle after the passageof the thread.

FIG. 3 is a lateral view illustrating the relations between the outerand inner shuttles and the drag in the free thread passage device of theinvention.

FIG. 4 is a top view illustrating the combination of the outer and innershuttles and the bobbin thread case of the invention.

FIG. 5 is a sectional bottom view of the foregoing.

FIG. 6 is a bottom view of a sewing machine bed equipped with the freethread passage device of the invention.

FIG. 7 is a diagram showing the function of the device for the freepassage of the thread according to the invention.

The free thread passage device of the invention comprises an innershuttle 12 rotatably fitted inside an outer shuttle 11 a cover 13provide at the front part of the said inner shuttle 12, a reverse lever15 to be fitted into a depression 14 of the said cover 13, a cam 16 withwhich to make the said reverse lever 15 function, and a drag with whichto arrest the rotation of the inner shuttle 12 as well as the bobbinthread case 17. The foregoing depression 14 is illustrated in thedrawing in the shape of a hole, which however can be replaced by asimple hollow.

The outer shuttle 11 has a removable arcuate lid 19 in the front partthereof. When the said lid 19 is fitted to the front part of the outershuttle 11 a groove 20 is formed between the lid 19 and the outershuttle 11. The said groove 20 is to receive the flange 35 on theexternal rim of the inner shuttle 12, the inner shuttle 12 being easilydetachable from the outer shuttle 11 by removing the lid 19. The lid 19is fastened to the outer shuttle 11 by a couple of metal clasps 21 whichare fixed to the outer shuttle 11. Each of the metal clasps 21, beingformed by bending a thin plate of spring steel, is rotatably pivotedwith a nut 22 on the rear face of the outer shuttle.

The front end 23 of the foregoing metal clasp 21 is so curved as tocover the front side of the lid 19 which is fitted to the front side ofthe outer shuttle 11, a protrusion 24 formed on the internal side of thesaid front end 23 being fitted into a hole 25, which is provided in acouple on the lid 19, thereby pressing the lid 19 from the outside tothe outer shuttle 11.

Therefore, the protrusion 24 and the hole 25 can be en gaged ordisengaged, taking advantage of the flexibility of the metal clasps 21,and hence the lid 19 can be easily disconnected from the outer shuttle11 by means of removing the metal clasps 21 from the lid 19 by revolvingthem in the outward direction.

The outer shuttle is fastened to the end of the shuttle shaft 28 fixedto the gear box 27 which is mounted on the lower surface of the sewingmachine bed 26 as illustrated in FIG. 6. The numeral 29 indicates theshuttle shaft driving lever shaft fitted to the lower surface of the bed26, the said lower shaft 29 and the shuttle shaft 28 being coordinatedby a gear inside the gear box 27.

It is a matter of course that the outer shuttle 11 is provided with abeak 30 with which to hook the upper thread. On the outside of said beak30 is formed a space within which to receive the upper thread hooked bythe beak as well as an arcuate plate 32 which is placed on the outsideof the beak and fastened with screws to the outside of the outer shuttle11.

The outer shuttle 11 is made of press molded steel plate, the boss 33being integrally fastened to the rear surface of the outer shuttle 11 bymeans of Welding. The lid 19 is also made of press molded steel plate orstrong synthetic resin, such as ABS resin and the like, with the resultthat the foregoing members can be produced economically and in lightweight with simpler processes and less materials than in the case offorming by means of the conventional lathe.

The inner shuttle 12 consists of an inner shuttle body 34 of pressmolded steel plate and a tubular cover 13 made by press molding a stoftsteel plate for deep extraction, the rear part of the said cover 13being fitted into the body 34, both the said members 13, 34 being spotwelded, an arbor 41 on which to journal the bobbin being welded into thebottom of the body 34. It goes without saying that, though the foregoingmembers are assembled by means of press molding and welding, the slidingparts thereof are subjected to the lathing and polishing finish. On theupper side of the cover 13 is provided an arm 36 with which to drag thebobbin thread case as well as a notch 38 through which to pass thethread drawn out of the bobbin 37 inside the bobbin thread case 17. Onthe right side of the said notch 38 is erected upward a protrusion 39for dragging, a window 40 being provided on the rear part of the notch38 so that the point of the descending needle may not be damaged.

The reverse lever 15 is fixed to the shaft 42, but it is so arrangedthat the said reverse lever 15 can be fixed to the shaft 42 at anyarbitrary angle by means of revolvably fitting the boss 43 of the lever15 to the shaft 42 and tightening the shaft 42 with a lock screw 44which is screwed into the boss 43.

The shaft 42 is revolvably borne by the bearing 45 provided at the frontpart of the position fixing plate 47 which is fastened to the lowersurface of the gear box 27. To the rear end of the shaft 42 is fixed acam lever 46.

The foregoing cam 16 is fixed to the shuttle shaft 28, but the positionof the cam 16 on the shuttle shaft 28 is adjustable as is the positionof the shaft 42 and' the reverse lever 15, it being so arranged that theangle between the outer shuttle 11 and the cam 16 can be adjusted.However, the cam 16 can be securely fastened to the shuttle shaft 28,since the position between the 4 shuttle shaft 28 and the outer shuttleis normally adjustable, as in the foregoing case.

The foregoing cam lever 46 is brought in contact with the said cam 16.As to the said cam lever 46, it is so arranged that the annularly curvedfitting part 48 thereof, revolvably fitted to the shaft 42, is fastenedto the shaft 42 by means of a locking screw 49 screwed into the saidfitting part 48, and hence the fitting angle of the cam lever 46 to theshaft 42 can be freely adjusted.

A pull spring 51 is extended between the cam lever 46 and the springreceiver 50 mounted on the position fixing plate 47, the cam lever 46being constantly pressed to the cam 16 by the force of the said spring51. The position fixing plate 47, provided with an oblong hole 52thereon, is fixed by screwing a locking screw 53 through the said oblonghole into the gear box 27. Accordingly, the position of the fixing plateis also adjustable.

The drag 18, made of a spring steel plate and bifurcated, is fastened tothe fixing frame 54 by mean of welding or the like method. The saidfixing frame which is curved as illustrated in FIG. 6 is fastened to thebed 26 by screwing locking screws 56 through the holes 55 of the fixingframe 54 into the lower surface of the bed 26. The diameter of each hole55 being slightly larger than the outer diameter of the threaded part ofthe locking screw 56, the position of the fixing plate 54 against -thebed 26 is adjustable, thereby permitting to adjustment of the positionof the drag 18.

The drag 18 is curvilinearly bent as illustrated in FIG. 3, the breadthbetween the internal sides of the right and left drags 18 being soarranged as to be slightly wider than the aggregated thickness of theprotrusion 39 of the inner shuttle 12 and the arm 36 of the bobbinthread case 17.

In FIG. 1, the numeral 57 indicates the needle plate with which to closethe window of the sewing machine bed 26, 58 indicating the needle hole,59 indicating the feeding teeth.

Now, the function of the device according to the invention is this: Thesame bobbin thread case 17 as that of the ordinary home sewing machineequipped with a semicircularly moving rotatory shuttle is fitted intothe inner shuttle 12, the thread 60 drawn from the bobbin 37 fitted intothe said inner shuttle 12 being drawn up ward through the inside of thenotch 38 provided on the cover 13 of the inner shuttle 12 and thenthrough the needle hole 58 of the needle plate 57.

Though not shown in the figure, the upper thread which is appropriatelyarranged on the upper part of the sewing machine is inserted into theneedle hole at the lower end of the sewing machine needle.

When the sewing machine is driven with cloth placed on the needle platein the foregoing state, the outer ishuttle 11 rotates in the directionindicated by the arrow, the sewing machine needle lowering, the beak 30of the outer shuttle 11 hooking up the upper thread passed through theneedle. The upper thread hooked up by the beak, forming a loop, travelsround the outside of the inner shuttle until the said thread is drawnupward and forms a stitch together with the lower thread.

When the outer shutter 11 rotates as described above, the inner shuttle12 is urged to rotate together with the said outer shuttle but remainsstationary as the protrusion 39 of the inner shuttle 12 is arrested bythe drag 18, the bobbin thread case 17 also remaining stationary, thearm 36 thereof being arrested by the protrusion 39.

Furthermore, according as the outer shuttle 11 rotates as describedabove, the cam 16 also rotates together with the outer shuttle 11, thecam lever 46 which is constantly in contact with the said cam 16oscillating according to the rotation of the said cam 16.

As the cam lever 46 oscillates, the shaft 42 and the reverse lever 15oscillate in coordination, with the result that the terminal part of thelever 15 goes in and out of the depression 14 provided on the cover .13thereby causing the inner shuttle to slightly reverse once per rotation,the timing of which is as set forth hereinunder.

' While the upper thread is traveling round the outside of the innershuttle 12, being hooked up by the beak and forming a loop, the camlever 46 is in contact with the lower part of the cam 16 as illustratedin FIG. 2, as a result of which the reverse lever 15 is lowered anddetached from the lower side of the inner shuttle 12. Consequently, theloop of the upper thread which travels round the outside of the innershuttle 12 freely passes between the lower side of the cover 13 and thereverse lever 15 without interference from the reverse lever 15.

At the time when the loop of the upper thread, which passed the lowerside of the inner shuttle 12, passes upward along the right side of theinner shuttle 12, having slipped off the beak 30, the terminal part ofthe reverse lever 15 fits in with the depression .14 of the cover 13 asillustrated in FIG. 1, thereby causing the inner shuttle 12 includingthe cover 13 to make a slight reversion, with the result that some spaceis formed between the protrusion 39 and the drag 18, the upper threadpassing through the said space without receiving any resistance.

The reversing function of the inner shuttler 12 by means of the reverselever 15 will be described in reference to FIG. 7. When the reverselever 15 is located in the position designated by the solid line in FIG.7, the end 61 of the lever 15 is disengaged from the depression 14formed on the tubular cover 13 of the inner shuttle 12, the depression14 of the cover 13 being located in the position indicated by the solidline in FIG. 7. At this juncture, the protrusion 39 is in contact withthe drag 18 in consequence of the rotation of the outer shuttle 11 asshow in FIG. 2.

When the cam 16 proceeds to the position indicated by the broken line inFIG. 7, the cam lever 46 and the reverse lever 15 being brought to therespective positions indicated by the broken lines in FIG. 7, the frontend 61 of the reverse lever 15 fits into the depression 14 of the cover13.

Since the moving direction of the front end 61 is along a circular arccentering on the shaft 42, the rear edge 62 of said end 61 which fitsinto the depression 14 causes the rear edge 63 of the depression 14 toreverse by the given angle as indicated by the broken line in FIG. 7. Asa result, space necessary for the free passage of the thread is formedbetween the protrusion 39 and the drag 18 as illustrated in FIG. 1.

When the loop of the upper thread passes between the protrusion 39 andthe drag 18 as described above, the loop of the upper thread is by nomeans caught in the drag 18, the said drag 18 being curved in the shapeof a smooth are as illustrated in FIG. 3.

The thread traveling smoothly with no resistance at the time of thethread passage, not only well tightened stitches are obtainable but alsothe noise at the time of the thread pasage can be prevented completely.

The cam lever 46 being constantly brought in contact with the cam 16 bythe flexibility of the spring 51, the usual noise owing to a collisionof the cam 16 against the cam lever 46 can be perfectly prevented.

The timing of the reversion of the inner shuttle 12 caused by thefitting of the end of the reverse lever into the depression 14 can befreely adjustedby adjusting the angle between the reverse lever 15 andthe cam lever 46 on the shaft 42 as Well as by adjusting the position ofthe cam 16 on the shuttle shaft 28.

As the lower thread travels to the needle hole 58 through the inside ofthe notch provided on the upper side of the cover 13, the said lowerthread is never brought backward any farther than the position of thenotch 38. As the lower thread is thus sustained steadily by the notch 38considerably ahead of the revolving range of the beak 30 of the outershuttle 11, there is no risk of the lower thread being hooked and brokenby the beak or being wedged between the outer shuttle 11 and the innershuttle 12. As a result, the outer shuttle 11 no longer requires theconventional thread arranging board with which to arrange the lowerthread so as not to be hooked by the beak.

As compared with the outer shuttle of the conventional full rotatorysewing machine, the outer shuttle 11 of the invention is lighter inweight and has less inertia during the rotation. Moreover, the distancebetween the center of the outer shuttler 11 and the contact point of theprotrusion 39 and the drag 18 is greater than that of the conventionalmachine, as a result of which the contact pressure is reduced.

Accordingly, even when the reverse lever should fail to functionsatisfactorily, resulting in insufiicient space between the drag 18 andthe protrusion 49, the passage of the upper thread through the saidspace is effected without any appreciable resistance, because not onlythe contact between the drag 1-8 and the protrusion 39 is not verystrong but the drag 18 performs a bulfer function as well It scarcelyhappens that the thread is wedged between the outer shuttle 11 and theinner shuttle 12, but even if such should happen, the lid 19 would pushthe front ends 23 of the metal clasps 21 thereby producing a spacebetween the groove 20 of the outer shuttle and the flange 35 of theinner shuttle and easing the resistance arising between the outershuttle 11 and inner shuttle 12, with the result that possible damage ofthe protrusion 39 and the drag 18 is prevented by the prevention ofstoppage of the rotation of the outer shuttle 11.

As the lid 19 is easily detachable by operating the metal clasps 21, theinner shuttle 12 can be disconnected from the outer shuttle 11 with easewhenever it is necessary to remove the thread or the like wedged betweenthe outer shuttle 11 and the inner shuttle 12.

As per the foregoing description, in the free thread passage device ofthe invention the passage of the thread is effected with extremesmoothness, beautiful regular stitches being obtainable with a smoothsewing performance, the noise being minimized, disassembling beingfeasible with ease for the removal of wedged thread or the like,efficient manufacture being practicable because of the fact that eachpart is produceable chiefly by press molding.

Moreover, the device of the invention has further distinguishedcharacteristics, for instance, the bobbin and the bobbin thread case ofthe commonly used home sewing machine equipped with a semi-rotatoryshuttle are utilizable without any adapter.

What is claimed is:

1. A device for providing free thread passage in a sewing machinecomprising an outer shuttle of the full rotary type mounted on saidsewing machine, an inner shuttle fitted into said outer shuttle, abobbin thread case re ceived in said inner shuttle, a protrusion erectedat one part of said inner shuttle, an arm provided on said bobbin threadcase, drag means mounted on said sewing machine for arresting rotationof said inner shuttle and said bobbin thread case by catching saidprotrusion and said arm when said outer shuttle rotates, reverse levermeans mounted on said sewing machine for causing the said inner shuttleto make a temporary rotation in a direction opposite to the direction ofrotation of said outer shuttle, and cam means for activating saidreverse lever means at an appropriaite moment.

2. A device for providing free thread passage as set forth in claim 1,further comprising a rotatable shuttle shaft mounted on said sewingmachine for said outer shuttle mounted on said shuttle shaft, said cammeans comprising a cam mounted on said shuttle shaft, a cam levercontacting said cam and adjustably fixed to a shaft which is revolvablyborne by a bearing mounted on said sewing machine adjacent said shuttleshaft, spring means for constantly urging said cam lever to contact saidcam,

7 and said reverse'lever means being adjustably mounted on said shaft.

3. A device for providing free thread passage as set forth in claim 1,further comprising a beak mounted on said outer shuttle, a coverenclosing the outside of said bobbin thread case and positioned at thefront part of said inner shuttle, said cover having at the lower sidethereof a depression into which the end of said reverse lever means fitsto cause said inner shuttle to make said temporary rotation, said coverhaving in the front part of the upper side thereof a notch which, byreceiving thread drawn from said bobbin thread case, maintains saidthread outside the path of said rotating beak, said arm extendingthrough said notch, and said protrusion being formed adjacent saidnotch.

4. A device for providing free thread passage as set forth in claim 1,wherein said drag means comprises an arcuately curved thin flexibleplate, said drag being mounted on a frame, said frame being adjustablyfastened to the lower surface of the bed of said sewing machine.

5. A device for providing free -thread passage as set forth in claim 1,further comprising a flange on the outer periphery of said innershuttle, arcuate lid means for preventing said inner shuttle from beingdetached from said outer shuttle by pressing said flange into saidouter.shut-. tle, metal clasp means fixed to said outer shuttle forpressing said lid means onto said outer shuttle, said lid means and saidouter shuttle being freely combinable and separable by revolving saidmetal clasp means. 1

References Cited UNITED STATES PATENTS 1,146,001 7/1915 La Chapelle1l2232 1,173,973 2/1916 Illig 1l2232 X 2,248,347 7/1941 Haas 1l2--232 X1,991,456 2/1935 Gouldbourn et a1. 1l22 32X ALFRED R. GUEST, PrimaryExaminer

